In C/C++ string literals "\" is used as escape character, normally used to introduce non-printing/control characters, like "\n" for newline, "\t" for tab, etc. To get a literal \ you have to write "\\", i.e. two backslash characters.
I've looked at the original code, it just uses a relative path to the .bmp file. To make that work you may have to adjust the working directory settings for your project (it looks to me like you are using Visual Studio; it is somewhere in the project settings - sorry don't have VS at hand for more precise instructions).

In C/C++ string literals "\" is used as escape character, normally used to introduce non-printing/control characters, like "\n" for newline, "\t" for tab, etc. To get a literal \ you have to write "\\", i.e. two backslash characters.
I've looked at the original code, it just uses a relative path to the .bmp file. To make that work you may have to adjust the working directory settings for your project (it looks to me like you are using Visual Studio; it is somewhere in the project settings - sorry don't have VS at hand for more precise instructions).